Stability, antioxidant activity and in vitro bile acid-binding of green, black and dark tea polyphenols during simulated in vitro gastrointestinal digestion

The stability and antioxidant activity of phenolic compounds, as well as the bile acid-binding activity of green, black, raw liubao and aged liubao tea during in vitro gastrointestinal digestion were evaluated. After in vitro gastrointestinal digestion, the total phenolic content of green tea remarkably decreased. However, it increased in the fermented black, raw liubao and aged liubao tea. Meanwhile, the total catechin recovery of green tea was 52.79%, but those of fermented black, raw liubao and aged liubao tea were 100.27%, 92.73%, and 106.02%, respectively. After gastrointestinal digestion, the ABTS cation radical scavenging capacity of black tea and aged liubao tea increased, and the post-fermented liubao tea increased more significantly. The in vitro bile acid-binding by tea extracts of green, black, raw liubao and aged liubao tea was 17.92-43.55%. Therefore, teas have potential for hyperlipidemic prevention associated with cardiovascular disease.